Edit string to concatenate word numbers in javascript

I would like to replace the string "The quick brown fox jumps over the lazy dog" with the string "The1 quick2 brown3 fox4 jumps5 over6 the7 lazy8 dog9".

Is there an cleaner, more elegant, sexier way?

String.prototype.concatWordNumber = function() {

   var myArray = this.split(' ');
   var myString = "";
   for (var i=0, len = myArray.length; i<len; i++)
   {      
        myString += myArray[i]+[i+1]+ " " ;
   }
  return myString;
}

var text = "The quick brown fox jumps over the lazy dog";

console.log(text.concatWordNumber());

Is there an cleaner, more elegant, sexier way?

I guess regex makes it more elegant and sexier, but your implementation is fine:

String.prototype.concatWordNumber = function() {
  var i = 1;
  return this.replace(/\b\w+\b/g, function(word) {
    return word + i++;
  });
};

Or you could use map:

String.prototype.concatWordNumber = function() {
  var plusIdx = function(x,i) {
    return x + ++i;
  };
  return this.split(' ').map(plusIdx).join(' ');
};

StackExchange Code Review Q#39699, answer score: 3